Genetics
by Shadowfax220
Summary: Sam is shocked to learn something about his brother that he never knew. What he learns brings grief to all the Winchester men. Oneshot.


**Genetics**

His youngest son was just too damn smart. He got it from his mother. Mary was smart too, she had told him they aught to tell the boys. And truth be told it wasn't that he'd been trying to keep it a secret, it just hadn't come up before this.

John Winchester was not sure how to tell his sons something he should have told them years ago.

"Dad," Sam said again. "That's not possible."

"Yes, it is son." John replied.

"What's not possible?" Dean asked looking from his brother to his father. They'd been stuck in this crummy little cabin for the better part of a week already. Tensions were climbing like they always did when the Winchester men were cooped up for too long.

He and John had been injured when the Sasquash they'd been chasing had managed to get a hold him during their last hunt. John had decided they needed to take a week or two off so he could heal.

"No it's not Dad. It's genetically impossible." Sam told him waving around the report on Dean's blood work the hospital had given Dean with his discharge papers. "Dean's blood type can not be B Positive if mine is O positive and yours is O Negative."

"Wait, you two are having an argument about what blood type I am?"

John ignored Dean's question. "Yes, it is," he said to Sam and waited for his son to think it out.

"Hey! Earth to Dad and Sammy! Are either of you going to answer me?" Dean said.

Sam was shaking his head at his father. "The only way that could happen is if..." Sam stopped and stared at his father his eyes wide. He looked at his brother then back to his father unsure what to say.

"Hello?" Dean said, "Will someone please tell me what the hell is going on! What is wrong with my blood type?"

John rubbed his beard and nodded at his youngest son. "I guess I should have said something sooner, but it never came up."

It was obvious to Dean that Sam had just found out something important. But for the life of him Dean didn't have any idea what they were talking about. "Will somebody please talk to ME!"

Shaking his head Sam looked at his father and said, "Tell him."

"Yes, please tell me." Dean said.

"Dean first, you have to know this is never something I meant to keep from you, it just… It never came up and frankly I never considered it to be important."

Dean looked at his father and asked, "Dad will you just spit it out."

"What your brother stumbled across was the differences in our blood types."

"I gathered that."

"Mary's blood type was O Positive. Mine is O Negative. Sam's is O positive."

"Right," Dean said, "And mine is B Positive."

"But Dean, that's not genetically possible." Sam told him, pain evident on his face.

"Of course it is Sam. I got my blood type from my birth mother. Not from Dad." Dean said shocking his brother even further.

"You knew?" both his father and his brother said at the same time.

"Hello. Not stupid here," he replied. "Of course I knew."

"But how," Sam asked. "How did you find out and why didn't you say anything?"

"Mom told me," he replied, "Well, sort of. She used to tell me most moms had to take what children God gave them. She said I was special because she got to choose me."

"Mary was so much smarter then me." John said.

"Yeah." Dean said with a laugh.

John looked at his oldest son and laughed, "You didn't have to agree quite so quickly."

"Of course I did," he said with a smirk.

"Dean," Sam asked, "Why didn't you ever say anything?"

"Because Dad's right, it isn't important," he told his younger brother. "I loved Mom. She is my mother the only one I ever knew. She always will be the only one I consider my mother."

John smiled at his son. Mary only had three years with Dean, but in that time she had managed to instill such love and a fierce loyalty in the boy. "She loved you too son."

Dean just nodded his head and looked away, but not before John was able to detect the watering of unshed tears in his eyes.

"So, I'm the only one freaked out by this." Sam said fiercely.

Dean turned to look at his brother, "Why would this freak you out?"

"Because…" he said, "I… Hell, I don't know. It just does. How did this happen?"

Dean's eyebrows shot up. "Sam, we had a talk some time ago about the birds and the bees," he said. "Do we need to give you a refresher course?"

"That's not what I mean. Come on Dean, this is huge and you know it." Sam said. "Who is she? Where is she?"

Dean's face lost all expression. "I don't know and I don't care."

John could tell by the total lack of expression on his oldest son's face that he did care and it did bother him. He was about to explain when Sam, with an exasperated sigh said. "What do you mean you don't care? Why not?"

"Because she obviously didn't want anything to do with me, why would I want to have anything to do with her?" Dean replied. "I don't care who she is."

It was John who replied this time, "That's not true son," he said sadly. "She loved you. It was me she didn't want."

Dean looked at his father and replied, "She has a very funny way of showing it. If she wanted me so badly why do I have no memories of her, none? If I was that important to her she would have visited me from time to time."

"She couldn't."

"Why not Dad, what could possibly stop a mother who cared about her child from visiting him occasionally and letting him know that she cared?" Dean hissed furiously at his father.

"Because she died when you were nine months old," John replied quietly.

Dean's growing anger suddenly calmed at his fathers soft spoken words. He opened his mouth to reply, but closed it again when he couldn't get the words out. Instead he stood up and walked out of the cabin.

"Dean…" Sam said and stood up to follow his brother. "Wait."

"Sam, let him go." John told his youngest son.

"Why dad, why didn't you tell him?" Sam asked bitterly. "Why make him suffer all these years."

"I didn't know." John said with regret. "I didn't even know Mary had told him."

Sam threw his hands in the air and walked away from his father frustration plain on his face. Needing something to do he grabbed their weapons bag, removed the contents and started cleaning them furiously.

John sat at the table and started reviewing the newspapers that were strewn on top of it. He knew this subject was far from closed, but both his boys needed time to adjust to the shock of what they had just found out.

Nearly an hour went by without a word being said. John looked up from the papers he'd been studying and watched his son as he feverishly cleaned their weapons. He stood, went to the fridge and pulled out two beers. After popping the top on both he took one to his youngest son and handed it to him without a word.

Sam accepted the drink and John started to return to his papers when Sam spoke up quietly, "I should have just dropped the subject," he said. "Why do I always have to push?"

John glanced at Sam and he realized that his youngest son was blaming himself for this whole thing. "Because you're just as stubborn as your old man," John said with a grin. Then, soberly he said, "It's not your fault Sammy. I should have discussed this with both of you a long time ago."

The door opened quietly while Sam and his father were talking and Dean walked in. "Then why don't we discuss it now," he said to his father.

"Dean," Sam said, relief at seeing his brother plain on his face. "Are you okay?"

Dean looked at his kid brother and saw the concern in his eyes. "Yeah Sammy, I'm fine," he said taking a seat next to his brother and picking up one of the shot guns. "You though, must be upset," he said.

"Why would you think that?" Sam asked. "You're the one who should be upset, not me."

"Because," he replied, "You are cleaning the guns, you've always hated cleaning them. And, because we just cleaned them yesterday."

"Yeah, well, you missed a spot on the ones you cleaned. I was just fixing your shoddy work."

"Dad's right, Sam," Dean said. "It's not your fault. I knew about it and should have asked him about it a long time ago."

"Are you ready for some answers now?" John asked bringing his oldest son a drink.

"Yes sir."

"Her name was Deanna Clemments and really I hardly knew her. I was stationed in Fort Hood down in Killeen Texas. We dated a few times, but it didn't take her very long to decide I wasn't what she was looking for in a man. She said I was too immature. And to tell you the truth, back then I probably was."

"When we broke up I had no idea she was pregnant. She never said anything to me. A few months later I left the military and moved back to Kansas. I met and married Mary and six months later someone from child services shows up at the door with you in her arms. She told us I was your father and that your mother had been killed in a car accident and she had no living relatives."

"I was in a state of shock, but not Mary, she just reached right out and took you from the social worker. She told her you had relatives right here and we would take care of you. I hardly said anything. I don't even remember half the things they talked about. Mary handled everything." He looked at his oldest son and said, "She loved you from the moment you were placed in her arms."

"Dad," Dean asked, "Do you have a picture of her?"

"No son, I'm sorry. Like I said, I really didn't know her very well. I met her during my wild times." He grinned at his son, "Believe it or not, I used to be as good as you with the girls. I'd have a different girl every week."

"What changed?" Dean asked.

"I met your mother, I met Mary," he said. "When you meet someone like her, it changes you."

They fell silent for a while each left to his own thoughts until Dean stood up and went to the table glancing at his fathers work. "Anything interesting?" he asked.

"As a matter of fact," John replied standing and joining his son. "There have been several disappearances over in Nevada that I think we need to check out."

Sam, not to be left out, joined them at the table as their father told them about the situation that had attracted his attention.

They couldn't help it, helping others out of bad situations was something all the men in the Winchester family would always do. It was in their blood.

**A/N – I know, I know… Not one single drop of action and it's not like me. I'm sorry but you can read my other stories for action. My story _Heyoka_ is filled with it, and so is _The Pack_. Please review and let me know what you think.**


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